1. Field of the Invention
The present invention relates to a patterning technique for semiconductor integrated circuits or the like, and more particularly to a new patterning method using both a template and a inkjet system.
2. Description of the Related Art
Photolithography is a general method for manufacturing integrated circuits or the like on silicon substrates or glass substrates. To form patterns using photolithography, a thin coat of photosensitive material, called resist, is applied on a silicon wafer and then the integrated circuit pattern, prepared on a glass dry template with photoengraving, is printed (transferred) with light. With the transferred resist pattern as a mask, the material beneath the resist is etched to form wiring patterns and elements. This photolithographic method requires processes such as resist application, exposure, and development, making it impossible to prepare fine patterns outside of a semiconductor plant or the like having facilities such as large scale equipment, power distribution facilities, and exhaust facilities. For this reason, other methods in a smaller scale for forming fine patterns have been researched.
For example, the method called MIMIC (micromolding in capillaries), for forming patterns using a mold, was disclosed in the Journal of the American Chemical Society 1996, No. 118, pp. 5722-5731. In this method, a template, whereon xcexcm-order grooved structures are formed of polymer, is placed on the substrate and liquid is caused by capillarity to infiltrate from the grooved sides. The template is made of polydimethylsiloxane and the liquid is a polymer, solution of polymer, colloidal solution, or the like. After the reaction between the liquid and the substrate is complete, the template is removed to reveal patterns formed upon the substrate.
In the abovementioned MIMIC method, however, the distance to which the liquid can be supplied from the sides of the template is limited because the liquid is spread by capillarity. A consequent problem is that large patterns cannot be formed using wide templates.
The present invention was made in view of the foregoing problem and, to that end, provides a patterning method, with which it is possible to pattern variously sized areas inexpensively and without large scale facilities, a patterning apparatus with which such patterning is possible, and a patterning template used in such patterning.
The inventors found that they could form fine patterns, without limiting the template size, by using a template having through holes and supplying the liquid in the necessary quantities for patterning through the holes in the template.
The patterning method relating to the present invention is a patterning method for forming patterns with liquid on the surface to be patterned (xe2x80x9cpattern surfacexe2x80x9d) by placing a template close to or essentially in contact with the pattern surface. This patterning method comprises the steps of placing the template close to or essentially in contact with the pattern surface; supplying liquid to the through holes, a plurality of which are established in the pattern transfer region of the template in order for the supply of liquid; and removing the template from the pattern surface after the liquid passes through the through holes and adheres to the pattern surface.
In the abovementioned patterning method, the template may be a concave template, convex template, or flat template. The surface of the template may be flat or curved. The pattern surface may be curved or flat. In other words, the pattern surface may be made of a hard material such as a substrate or a flexible material such as film.
The liquid may be ink, or an organic material or inorganic material, so long as it has a viscosity allowing it to be supplied through the through holes. The liquid may also be a colloidal solution including fine grains. For example, various colloidal solutions, such as the following can be used: solution for forming black matrix comprising carbon powder dispersed in a solvent, solution for forming transparent electrodes comprising transparent electrode material dissolved in solvent, and solution for forming electrode patterns comprising metal fine grains dispersed in a solvent.
The pattern transfer region may have either uniform patterning or be prepared with a specific pattern. When photolithography is used in preparing the template, any pattern can be formed by adjusting the exposed region.
Each through hole in the template functions as a nozzle which supplies liquid to the pattern surface. The location and number of through holes in the template is not limited so long as it is possible to supply liquid to the pattern transfer region of the template. Through hole diameters and numbers of through holes, whereby it is possible to supply sufficient liquid in a short period of time, may be provided. It is preferable that the method for supplying liquid to the through holes be a method for applying pressure to the liquid, such as an inkjet system, because such method is fast and controllable. Also, natural liquid supply, so as to supply liquid to the through holes by capillarity, can be used. Capillarity and forced supply means such as an inkjet system may also be combined. Any material may be used as the template material so long as it has the physical strength to sustain patterning and is chemically inert with respect to the liquid. It is especially preferred that the template be constituted of a porous material or permeable material in order to naturally eliminate air after the liquid is supplied.
Below are concrete examples of the abovementioned patterning method relating to the present invention. In the abovementioned template, for example, the through holes may be disposed along the patterning region. In that case, the step for supplying the liquid is a step wherein liquid is supplied by pressurizing all the through holes established in the template.
Also, the through holes may be established uniformly in the abovementioned template. In that case, the step for supplying the liquid is a step wherein liquid is selectively supplied with an inkjet system to only the through holes disposed in the pattern transfer region from among all the through holes established in the template.
Furthermore, the abovementioned template may be constituted of a porous material. In the step where the template is separated from the pattern surface, the template is separated from the pattern surface after excess liquid supplied via the through holes is absorbed by the porous material.
The patterning apparatus relating to the present invention is a patterning apparatus for placing a template near or essentially in contact with a pattern surface and forming patterns with liquid on the pattern surface. The patterning apparatus is provided a template transport mechanism for placing the template near or essentially in contact with the pattern surface; a liquid storage mechanism for storing the liquid; a liquid supply mechanism for supplying the liquid from the liquid storage mechanism to the plurality of through holes established in the pattern transfer region of the template; and a control apparatus for controlling the transport of the template by the template transport mechanism and the supply of liquid by the liquid supply mechanism.
In the abovementioned patterning apparatus, the control apparatus causes the template to be placed near or essentially in contact with the pattern surface, liquid to be supplied via the through holes by the liquid supply mechanism, and the template to be removed from the pattern surface after the liquid adheres to the pattern surface.
The liquid storage mechanism is only required to store liquid by some method and, for example, comprises a tank for holding liquid and a pipe or the like through which liquid flows from the tank.
The template transport mechanism is a mechanism which can change the relative positions of the template and pattern surface; the template transport mechanism may transport the template, transport the substrate or the like having the pattern surface, or transport both.
The liquid supply mechanism may supply liquid by force using an inkjet system or the like; and may also have a constitution whereby the liquid is supplied naturally from the liquid reservoir using capillarity. In the case of an inkjet system, the liquid supply mechanism may have a constitution wherein liquid can be expelled from inkjet recording heads at the desired locations on the template. In this case, the liquid supply mechanism also includes a head transport structure constituted so as to vary the relative positions of the template and inkjet recording heads.
For example, the abovementioned template has the through holes disposed along the pattern transfer region and the liquid supply mechanism is provided a pressure chamber for supplying liquid to all the through holes in the template and a piezoelectric element which deforms at least one wall surface of the pressure chamber and changes the volume of the pressure chamber.
For example, the abovementioned template has through holes disposed uniformly therein; the liquid supply mechanism is provided inkjet recording heads constituted so as to expel the liquid and a head transport mechanism for transporting the heads to certain through holes established in the template. The control apparatus causes the heads to move and supply liquid to those through holes which are located in the pattern transfer region.
Furthermore, the abovementioned template is constituted of a porous material and the control apparatus removes the template from the pattern surface after the excess liquid supplied via the through holes is absorbed by the porous material.
The patterning template relating to the present invention is a patterning template for forming patterns by adhering liquid to a pattern surface. The pattern transfer region of the template is in the form of a concave template and a plurality of through holes is established in the pattern transfer region.
The patterning template relating to the present invention is a patterning template for forming patterns by adhering liquid to a pattern surface. The pattern transfer region of the template is in the form of a convex template and a plurality of through holes is established in the pattern transfer region.
Furthermore, the pattern transfer region of the template is in a form exhibiting an affinity for the liquid; the region other than the pattern transfer region (xe2x80x9cthe non-pattern transfer regionxe2x80x9d) is in a form exhibiting a non-affinity for the liquid; and a plurality of through holes is established in the pattern transfer region.
Here, affinity and non-affinity are determined based on the properties of the liquid, which is used for the patterning. For example, if the liquid is hydrophilic, a hydrophilic composition exhibits affinity and a hydrophobic composition exhibits non-affinity. Oppositely, if the liquid is lipophilic, a hydrophilic composition exhibits non-affinity and a hydrophobic composition exhibits affinity. The liquid may be varied in different ways according to the industrial application.
For example, the abovementioned template is formed so that the pattern transfer region has the subject pattern. Also, the abovementioned template may be formed in a standard pattern wherein the pattern transfer region is uniformly arranged. The abovementioned template may be formed of porous material. Furthermore, the inner walls of the through holes formed in the abovementioned template may be formed so as to exhibit non-affinity for the liquid.
The method for manufacturing the patterning template relating to the present invention is a method for manufacturing a patterning template for forming patterns by adhering liquid to a pattern surface, comprising the steps of: forming a resist layer on the base; exposing portions of the resist layer according to a pattern; developing the exposed resist layer; etching the base with the developed resist as an anti-etching mask; coating the etched base with porous material; curing the porous material applied; separating the cured porous material from the base; and forming a plurality of through holes in the pattern transfer region of the separated porous material to form the template.
In the abovementioned method for manufacturing the patterning template, exposure may mean forming a mask in the resist layer and irradiating it with light or exposing the resist to the prescribed pattern using a laser beam pickup with positional selectivity. The resist layer may be positive type or negative type. The type of resist layer and exposure region are determined according to whether the template is a concave or convex template.